    Introduction
This is a time of tremendous change for music “Radio”: the broadcast of audio musical performances to the listening public. In the past, such broadcasts took place exclusively over the “air” with only limited (e.g. telephonic) opportunity for direct feedback from listeners. Today Internet audio streaming of music is rapidly increasing, and Radio Stations are finding they have proven, viable brands and audiences they can leverage and serve in this new medium.
As a result of this change in requirements for music radio, unique demands have been placed upon the scheduling of musical performances. The present invention provides a method of scheduling performances that can be applied to radio broadcasting as well as to other areas of commerce. Within the radio industry, the method is capable of generating music playlists that can be used in traditional over-the-airwaves radio broadcasting or in internet-based radio. This scheduler achieves or exceeds the objectives of professional music scheduling systems, and it introduces new capabilities that address the new requirements for internet radio. It is a demand-based, goal-oriented scheduler (rather than a rule-based model). In the radio music scheduling domain, it achieves professional-level scheduling with the option of dynamic format customization based on inputs from other sources such as—in the case of internet application—listener preferences being fed back.
As used herein, the term “media performance”, abbreviated “MP” is a generic term intended to embrace all types of media performances. These include audio performances (musical or otherwise), advertisements or commercials (as might appear on television or on the web, for example); video performances (such as broadcast television performances); animation (e.g., computer-generated clips); web page elements (banner ads and the like) and even web pages themselves. All such media performances or “MPs” require scheduling. By way of example, and as a best mode of practicing the present invention, the present invention will be described in connection with music scheduling at a radio station.
The ‘Art’ of Music Scheduling at a Radio Station
The art of music scheduling consists of selecting a sequence of musical performances, from a finite library, to compose a schedule. The primary consumers of automated music scheduling systems are Radio Stations, who use them to determine the sequence of musical performances played on air. A salient characteristic of music schedules is that musical performances are repeated, i.e., that the library is finite, and that listeners are interested in hearing musical performances more than once. So music scheduling systems are concerned with both the relationships between different musical performances in the schedule, and the relationships between different occurrences of the same musical performance, in particular the frequency and spacing between occurrences.
Consumers of automated music scheduling systems have several objectives:                Play musical performances at different frequencies/rotations                    Ensure that current hits play more frequently than older musical performances.                        Maximize library variety        
If a station has a limited number of musical performances with a particular “attribute” (e.g., “rap music”) such performances should be spread out over time rather than appear in bunches. If a station has a lot of a particular kind of musical performance, they too should be spread out so as to avoid getting in a “rut,” where the listener's perception will be that that is the only kind of music played by the station.                Avoid clashes                    Musical performances with certain characteristics do not work well when played adjacent to other musical performances with the same or other characteristics. Adjacencies between such musical performances should be avoided.Prior Art of Music SchedulingRule-based Music Schedulers                        
There are several known commercial systems for automated music scheduling for radio broadcasters. These systems allow radio programmers (Program Directors or “PDs”) to enter musical performance (“MP”) data, including many MP attributes. MP's are assigned to category queues, and “clocks” are defined, which are schedule templates (typically an hour long) consisting of a sequence of categories. Rules are defined, such as “Don't play MP's with this attribute next to MP's with that attribute,” or “Don't play two MP's by the same artist closer together than 90 minutes.” Scheduling consists of “filling in” the clocks following the rules. For each clock position (which consists of a request for an MP from a particular category), some subset of MP's from the front of that category queue are tested for success in passing the various rules. The most successful MP is placed in that position in the schedule, and then moved to the back of the category queue.
Two significant characteristics of basic music scheduling systems are:                Musical performance play frequency is derived from category membership and the clocks                    If an MP is one of ten MP's in category A, and category A is called for twice per hour in the clocks, then that MP (and all MP's in category A) will have an average play frequency of “once every five hours.”                        Rules contain many fixed values (such as durations and counts)        
Rules must be set with full and complete knowledge of the music library, and with considerable effort and skill, in order to ensure that they are satisfiable, and accomplish the scheduling objectives.
Personalized Music Scheduling
Personalized music services are a recent phenomena, made possible by the web and audio streaming technologies. Most allow listeners to rate musical performances on some scale: on a scale of 1 to 10, thumbs up or down, etc. Some allow listeners to rate artists and albums as well. Some systems use this information to create a custom schedule, others use it to place listeners in a pool with people of similar tastes, all of whom get the same schedule. Some systems allow listeners to “ban” musical performances/artists/albums so that they no longer appear again. Some systems allow listeners to select a predefined “station,” either one provided by the service or a terrestrial broadcast station, to serve as the starting point for their personalized schedule.